J99 Microphone Preamp

The SCA J99 is a flexible, high-gain, low-noise, low-distortion microphone preamplifier, based on the classic Jensen Twin Servo design. This is a great preamp to use when a neutral sonic character is required, but the slightest amount of euphonic transformer coloration is desired.

990C-style op-amps must be ordered separately.
CH02-SP-J99 subpanel must be ordered separately.

This product is no longer available

Features

High Gain

The J99 can provide 70dB of gain which includes the voltage step-up provided by the input transformer. Jumpered for 300 ohms input impedance, the maximum gain available is not quite 76dB.

Low Noise

With an EIN approaching -130dB, the J99 is quiet enough to use in virtually any recording application, especially with low-output ribbon mics.

Dual DC Servos

The J99 has a DC servo for each op-amp and uses no capacitors in the signal path.

Stepped Gain Control

A 12 position Grayhill switch provides accurate and repeatable gain settings in 5dB steps from 15dB to 70dB.

Gain Trim

Since 5dB is often too big a gain step, the A12 also has a gain trim control, which provides up to 6dB of cut at any gain setting. This allows very fine adjustment of gain between steps.

Phase Reverse

Inverts the signal phase.

Phantom Switch

Slow-rise phantom power minimizes pops and thumps.

Neutrik Connectors

High quality PC mount connectors eliminate cabling and ease assembly.

Lundahl Input Transformer

The J99 uses a Lundahl 1538XL to couple the microphone signal to the amplifier. This transformer is used in a number of high-end preamps and it provides superior performance in a compact package.

On-board voltage regulators can accommodate power supplies from +/-15VDC up to +/-35VDC, allowing the use of op-amps with +/-24VDC requirements. Potentiometers allow easy voltage adjustment, making experimenting fast and simple. Local regulation also keeps inter-channel crosstalk extremely low when multiple preamps share the same power supply.

2520 Compatible

The J99 will work with a number of discrete op-amps from manufacturers such as API, Millennia, Forssell, Old School Audio, and John Hardy. High quality IC amplifiers such as the AD797 and OPA627 can be fitted directly to the board as well and can rival the discrete types when extreme headroom is not required.